Passively sitting and waiting to be attacked is something we train in for the first couple of years of learning aikido, but after that we should really be moving to a more proactive approach. Look at O'sensei's original training manual: In the explanations the first step always comes from Tori (admittedly, that first step is sometimes "Tori fills their body with ki and invites uke to attack" - but its not passive, and fewer than half the techniques listed there).

The one time I've had to use aikido, I was in the middle between two people who were getting progressively angrier with one another -- a younger man and an older man. I'm not going to go into details, but I'm related to both and was trying to calm things down. As things got worse, I remember thinking that if the younger guy moves, I'm going to take him down. He moved, and I took him down.

In a sense, you could say that I attacked him with aikido -- he actually moved away from me. I did a beautiful kyzushi that lead into a great pin that immediately calmed things down and left my no-longer-quite-as-angry young friend unhurt. I, on the other hand, tenkaned right into the back of a wooden chair and had a very nasty bruise for the next week or so.

The point is, I didn't wait for him to move before deciding to take action. I decided to take action and then he moved.

To flip things around, could he have done anything after I attacked him? Probably. It would have been difficult while I was throwing him, but if he had wanted to continue to struggle after I took him to the floor, it could have gotten nasty. I was lucky that he calmed down right away.